The present invention relates to a process for preparing textile floor coverings in motor vehicles, and a resultant product.
Textile floor coverings for motor vehicles are known per se. They are usually prepared by initially forming a textile floor layer in the form of a matrix of a floor panel of a motor vehicle. Thereby, due to the transmission tunnel or elevations and cavities being situated on the floor panel, thickness differences in the layer ranging from a few millimeters to some centimeters are produced.
Usually, velours or needled felt carpets which are coated on the backside are used. The carpets in high-quality cars are supplied with a so-called heavy layer to improve the sound insulation. This may be, for instance, an EPDM sheet containing up to 70% filler by weight.
The thus obtained laminate of backside coated carpet and heavy layer is usually subjected to a deformation to generally match the shape of the floor panel.
In order to equilibrate the unevenness of the floor panel, and for sound absorption, an absorption foam backing layer is formed according to the state of the art by means of an injection process performed on the above mentioned laminate. Particularly, it is preferred according to the state of the art to use a filled two-component polyurethane foam (heavy foam) which is injected into a mold. This polyurethane foam is effective as an acoustic dampener in combination with the heavy layer.
A particular problem arises if one attempts to include small plastic foam pieces (off-cuts), e.g., recycled off-cuts, in the absorption foam layer. Difficulties arise in maintaining an even density of the absorption foam layer. This density is preferably completely uniform over the whole area of the textile floor covering, since varying densities cause perturbations of the sound absorption system and, therefore, a diminished acoustic efficiency. Proper introduction of the material into the mold is difficult due to the low density and shape restoring elasticity of the plastic foam off-cuts. Even the presence of a suitable binder cannot resolve these problems.
From DE 40 15 413 A1 the preparation of a formed part of any form and size is known from recycling materials. The formed parts are made of foams, particularly waste foams which are torn into an off-cut form and are intensively mixed with a one-component-binder on the basis of corn and/or wheat starch. A bonding of the formed parts to other objects is not described.
DE 34 30 775 C2 relates to a carpet part, a process for the production thereof, and its use. According to this document, a carpet part for sound insulation, particularly in motor vehicles, is provided, made of a carpet and a heavy layer situated underneath it, or forming an integral whole with the carpet, and a synthetic lower layer being placed beneath it, whereby the lower layer is made of a combination of foam or non-woven fabrics having different fluid resistances. The sequence of the layers is, for instance, carpet, heavy layer, foam layer having a relatively high fluid resistance and a foam layer having a relatively low fluid resistance.
According to the state of the art, it was not possible up to the present to successfully integrate foam off-cuts into an absorption foam backing layer of a textile floor covering for a motor vehicle.